1. Field of the Invention
The present invention relates generally to the network technology and more particularly, to a session-based dynamic bandwidth allocation applied to passive optical network.
2. Description of the Related Art
As the Internet-based applications become diverse, many application programs are based on session and developed into peer-to-peer and point-to-multipoint from the traditional client/server architecture. Most of multimedia streaming application services adopt session mode, which is characterized in that the data channel is dynamically determined in the course of communication establishment and the mediate formats are exchanged dynamically, such as session descript protocol (SDP). Thus, the network packet not only fails to determine the application species from the pure IP address and TCP/UDP port but fails to accurately assess the required bandwidths for the application services beforehand.
In addition, taking passive optical network (PON) as an example, uplink bandwidth is the resource shared by all optical network units (ONU), so state reporting dynamic bandwidth allocation (SR DBA) or traffic dynamic bandwidth allocation (TM DMA) is generally adopted for dynamic bandwidth allocation. However, neither SR DBA nor TM DBA could apply immediate and accurate dynamic allocation to the required bandwidth of every ONU.
U.S. Pat. Pub. No. 2008/0273878 A1 disclosed a method for mapping a service flow to a service transmission channel, which includes the steps of configuring configuration parameters for a message characteristic into an optical network terminal (ONT); and mapping a service flow to a specified service transmission channel when it is determined that the service flow matches the configured message characteristic after the service flow is received by the ONT.
Taiwan Pat. Laid-open No. 2008/24346 disclosed a method of Ethernet passive optical network dynamic bandwidth allocation in consideration of service quality. This method is to inspect the control codes regarding connection establishment and disconnection of application services in the information contents of the application services via a detector and the output of the detector is connected with a bandwidth state report unit of a customer premise equipment of the optical network; the bandwidth state report unit gives the required bandwidth a queue length; the bandwidth allocation unit located at optical line terminal (OLT) inspects queue length report column content of received report message to know the user's bandwidth requirement and then allocates adequate bandwidth to ONU for use. However, such conventional bandwidth allocation method still fails to apply immediate and accurate dynamic allocation to the required bandwidth of every ONU.